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Fork Oil

Just looked it up in my HD service manual and it dosen't require it untill 50,000 miles, Harley use to require it sooner, then they found the fluid is good for 50,000 miles so they updated the service schedule so the consumer was not spending their money needlessly. The tech dept at the factory told me the 50,000 miles retro back to earlier models also.
 
Changed mine at 21K. Old oil smelled like burnt fish oil. Replaced with Belray 10 Fork oil. Difference in handling was AMAZING. My advice is chage as soon as you buy the bike.

07FLHTCUI
 
Changed mine at 21K. Old oil smelled like burnt fish oil. Replaced with Belray 10 Fork oil. Difference in handling was AMAZING. My advice is chage as soon as you buy the bike.

07FLHTCUI

That is because it was fish oil. Same thing they have been putting in commercial refrigeration compressors for years. I think it goes by the name of "Capella D" or something like that. Just for kicks and giggles one time, many years ago, I put a drop of that fish oil on the hood of an old Ford. A couple hours later that drop had spread to nearly 1/2 of the hoods surface. Slippery stuff for sure. Oh ya, many of our American made Harleys have had Japanese Showa forks on them for years.
 
You have cartridge forks on your bike, so the procedure linked below may not work for you. I changed the fork oil in my '07 FLHX and did a write-up on other forum.

Well, I didn't wait 'til tomorrow and did the fork-oil change earlier this evening. It took me about an hour to do the job using the top-fill method. It was mostly a piece of cake, and here's the blow by blow doing one side at a time:

1. Remove ignition switch and the two screws holding the inner-fairing cap. Lifting the cap out of the way gives access to the fork top plug. I tried a 36mm socket but there wasn't room, same for a crescent, but the 36mm wrench in the tool kit was the solution. The plug is not on tight and removal is easy.

2. I used a ½" clear plastic tube cut to about 10" in length and inserted a small funnel on one end and stuck the other end into the fork top. It was a tight fit but worked. I wire-tied the funnel to the handlebars to keep it from slipping. Put a plastic bag on the tank to protect it from fluid that might spill out of the funnel.

3. Once the top plug is removed the vacuum is released, so draining should be no problem. It indeed wasn't once the bottom drain plug was removed, and that was the biggest problem of the whole job. Those damn Phillips screws were in very tight and I almost couldn't get them off. Don't even try to remove them with a Phillips screwdriver, but instead get a #3 Phillips bit and use a 3/8" or 1/2" ratchet, putting heavy pressure on the screw while you turn it. It was close, but I got both of them without stripping the head after rapping moderately with an impact screwdriver (not an impact wrench).

3. Once this screw is out the fluid begins to drain. My right side came out slowly at first until I used a toothpick to loosen some gunk that partially plugged the hole. There is no need to pump the forks to release all the oil, as in time (about 5 min.) the oil completely drains, all 10.8 oz. of it. It is a black, smelly fluid that doesn't resemble any hydraulic or other oil I've ever encountered. It looks like it has moly or graphite in it. Once the old fluid is out, reinstall the screw, but there's no need to tighten it as much as was done at the factory. The manual says 78-96 inch-pounds.

4. I filled with SE Heavy (not the Extra Heavy variety), which is reportedly 15w (stock is 10w). Note that RK's require 11.1 oz., while EG's are 10.8 oz. Fill slowly about 2-3 oz. at a time, then pump the forks each time to force the oil past the damping valve. After about 3-4 pumps you start hearing a hollow sucking noise, which suggested to me that it had cleared the valve. RK's may not need to do this step-by-step pumping approach since they don't have the damper valve installed. That process took maybe 10 min. for each side.

5. Finally, replace the top plug, do the other side as above, then replace the inner-fairing cap and ignition switch.

This is definitely the way to change the fork oil on these bikes, IMO, and I may do this job every 10k, certainly not more than every 20k. As I said, it took about an hour, but next time I think I could do it in 45 min. now that I know the routine. Thanks to all who encouraged me to try this method.

A ride revealed a slightly firmer feel to the front-end with the SE fluid, but it is not harsh. Corners felt very secure, but my 10-mile ride didn't give it a good test for bottoming, etc. It felt taut and secure, however, and these early results are positive.

Harley%20Fork%20Oil%20Change.jpg

As others have mentioned, the original fish oil looked and smelled like something you would want out of the forks ASAP, and I replaced it with SE Heavy #99881-87 (not the Extra-Heavy Racing oil). This firmed the ride but in a positive way by eliminating bottoming and giving more control. IMO although its firmer it did not make the ride harsh.

Changing the oil was an easy one-hour operation on my bike, and this procedure should work the same for all non-cartridge forks. Anybody with cartridge forks like the OP want to try this out?
 
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